US 12,345,154 B2
Untethered logging devices and related methods of logging a wellbore
Mohamed Larbi Zeghlache, Al Khobar (SA)
Assigned to SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Sep. 14, 2022, as Appl. No. 17/932,139.
Prior Publication US 2024/0084697 A1, Mar. 14, 2024
Int. Cl. E21B 47/13 (2012.01); E21B 23/04 (2006.01); E21B 47/12 (2012.01)
CPC E21B 47/138 (2020.05) [E21B 23/04 (2013.01)] 20 Claims
OG exemplary drawing
 
17. A method of logging a wellbore, the method comprising:
isolating a ballast weight within a buoyancy chamber of an untethered logging device,
wherein the buoyancy chamber is delimited by:
a lower surface of a housing of the untethered logging device, the lower surface establishing an uphole end of the buoyancy chamber,
an inner surface of a discharge door configured to release the ballast weight, the inner surface defining a downhole end of the buoyancy chamber, and
a chamber wall externally extending from the housing;
dropping the untethered logging device in a downhole direction through the wellbore;
automatically opening the buoyancy chamber at a predetermined position within the wellbore;
releasing the ballast weight from the buoyancy chamber to reduce a bulk density of the untethered logging device; and
flowing the untethered logging device in an uphole direction through the wellbore.